Black, the former boss of Hearst Magazines, had taken the job despite having no experience in education, in what was widely (and hostilely) received as an act of pluto-/technocratic overreaching by the mayor. Today, Bloomberg said he took "full responsibility" for the failure of the appointment.

That responsibility was not, however, retroactive to his original decision. The mayor praised his new chancellor-to-be, deputy mayor Dennis Walcott, as the ideal candidate to run the schools. Why, a reporter asked, had the mayor not picked Walcott as the chancellor in the first place? "Because I picked someone else," Bloomberg said.

The problem with the media executive turned chancellor, the media executive turned mayor implied, was the media. "We both agreed that the story had really become about her and away from the kids, and that's not good," he said. "We've got to focus on what's right for the kids."

Was the press responsible for the switch? "It is what it is," Bloomberg said.

If this was dissatisfying, too bad. "The questions here should be about how Dennis is going to take education forward," Bloomberg said.

Finally, obligingly, a reporter asked Walcott one question about what the appropriate emphasis on testing should be. As soon as the chancellor-to-be finished answering it, the mayor declared the press conference over.

March 3 2015 1:39 PMThe “Most Pleasurable Portrayal of Libertarianism“ Bonus SegmentDavid, Emily, and John discuss what Parks and Recreation got right about government.Emily Bazelon, David Plotz, and John Dickerson